Hi Shaohua, On 2017/10/16 11:22, Hou Tao wrote: > Hi, > > On 2017/10/14 3:21, Shaohua Li wrote: >> On Fri, Oct 13, 2017 at 06:36:31PM +0800, Hou Tao wrote: >>> For a RAID1 device using a file-based bitmap, if a bitmap write error >>> occurs and the later writes succeed, it's possible both BITMAP_STALE >>> and BITMAP_WRITE_ERROR bit will be written to the bitmap super block, >>> and the BITMAP_WRITE_ERROR bit in sb->flags will make bitmap_create() >>> to fail. >> >> Why don't clear the bit in the 'latter succeeded write'? > > It will work too. Cleaning after read can ensure that after upgrading the > kernel we can activate the RAID1 successfully event if the write error > bit had been written to the bitmap. If you are OK with the fix which clears BITMAP_WRITE_ERROR before write, I will send a v2 patch. Regards, Tao >>> So clear it to protect against the write failure-success case. >>> >>> Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx> >>> --- >>> drivers/md/bitmap.c | 9 +++++++-- >>> 1 file changed, 7 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c >>> index d212163..97c423a 100644 >>> --- a/drivers/md/bitmap.c >>> +++ b/drivers/md/bitmap.c >>> @@ -688,8 +688,13 @@ static int bitmap_read_sb(struct bitmap *bitmap) >>> } >>> } >>> >>> - /* assign fields using values from superblock */ >>> - bitmap->flags |= le32_to_cpu(sb->state); >>> + /* >>> + * assign fields using values from superblock >>> + * clear BITMAP_WRITE_ERROR bit to protect against the case that >>> + * a bitmap write error had occurred and the later writes had >>> + * succeeded. >>> + */ >>> + bitmap->flags |= (le32_to_cpu(sb->state) & ~BIT(BITMAP_WRITE_ERROR)); >>> if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN) >>> set_bit(BITMAP_HOSTENDIAN, &bitmap->flags); >>> bitmap->events_cleared = le64_to_cpu(sb->events_cleared); >>> -- >>> 2.5.0 >>> >> >> . >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > > . > -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
